US2151493A

US2151493A - Valve control unit

Info

Publication number: US2151493A
Application number: US130141A
Authority: US
Inventors: George H Acker
Original assignee: Cleveland Worm & Gear Co
Current assignee: Cleveland Worm & Gear Co
Priority date: 1937-03-10
Filing date: 1937-03-10
Publication date: 1939-03-21
Anticipated expiration: 1956-03-21

Description

March 21, 1939. ACKER 2,151,493

VALVE C ONTROL UN I T Filed March 10, 1937 2 Sheets-Sheet l QHHHMNW 9 Z- INVENTOR.

ATTORNEY;

March 21, 1939'. G. H. ACKER VALVE CONTROL UNIT ,2 Sheets-Sheet 2 Filed March 10, 1937 INVENTOR. @eorge 7% 06%61 BY n W {7W (77 ATTo'RNEYs,

. 5 in the valves.

Patented Manfil, 1939 UNITED STATE VALVE NTROL UNIT George H. Acker, Shaker Heights, Ohio, assignor to The Cleveland Worm & Gear Company, Cleveland, Ohio, a corporation of Ohio Application March 10,

Claims.

The present invention relates to a power driven mechanism for operating valves wherein the opening and closing action of the valve element, such as a gate or a disc, is dependent upon the movement of a valve stem.

A valve control unit of the character to which my invention pertains consists essentially of a drive motor, a reduction gear train and electric control switches actuated by forces .and movements of the gear train,.and adapted to start and stop the drive motor. The driven shaft of the gear train of such a unit is so connected to the 'valve stem that its rotation is effective to produce opening and closing movement of the valve stem As the valve element such as the ggte or disc approaches its closed position in the v very rapidly, and its amount of further movement is very slight, which means that the power driven valve control unit must be capable of delivering excess torque and then stopping immediately upon the valve closing stroke. Since the moving parts of a power source, such as the shaft and armature of an electric motor develop a substantial kinetic energy during operation, and even after cessation of actuation of such a motor, this kinetic energy must still be absorbed by the other elements of the valve control unit such as the valve, the valve stem, and the reduction gear train.

It is therefore the general object and nature of my invention to provide means for automatically disconnecting the drive motor from the remainder of the mechanism when the valve has reached its proper seated or closed position, so that the kinetic energy of the drive motor will not be applied to the remainder of the mechanism, but can be freely dissipated.

My invention also provides means for insuring the delivery of required torque to the valve operating element during the final stage of the valve closing stroke so as to insure a proper seating of the valve.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description setforth in detail certain mechanism embodying the. invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexeddrawings: Fig.1 is a sectional view of a valve control unit ve seat, its resistance to movement increases 1937, Serial No. 1363.141

embodying the principle of my invention, such section being taken substantially in the plane of the reduction gear drive shaft; Fig. 2 is a view of the control switch compartment of the valve control unit, and with the cover plate removed; Fig. 3 is a sectional view of the unit taken substantially upon a plane normal to that of Fig. 1 and along line 3--3 thereof; and Fig. 4 is a sectional view, also taken upon a plane normal to that of Fig. l and substantially along line 4-4 thereof.

Now referring more particularly to the drawings, the device shown therein includesa housing 1, one end of which is closed by an adapter plate 2 having an external face upon which the drive motor (not shown) is mounted. A worm shaft 3 carrying the worm 4 is journalled in the housing I by the

bearings

5 and 6. The worm 4 is axially slidable by means of a spllnecl connection with the shaft 3 in order to produce a hammer blow effect in the operation of the valve control unit. This latter feature is not claimed as a part of the present invention, since it is more fully set forth, particularly pointed out, and distinctly claimed in my co -pending application Serial No. 123,735, filed Feb. 2, 1937.

2 A worm wheel 1 keyed to the shaft 8 is driven by the worm 4. The shaft 8 has an exteriorly projecting portion 9 which can be directly connected to a valve stem or indirectly connected to a valve stem nut by means of spur gearing, such nut being carried by the valve yoke. Such latter types of connections are well known in the art and hence are not here illustrated or further described.

A helical gear III is mounted on the right hand end of the worm shaft 3, as shown in Fig. 1. The gear 10 meshes with another helical gear ll carried by the drive shaft l2, and is connected thereto through a helical spline l3. The shaft I2 is iournalled at one end in the bearing l4 and its other end is keyed to the coupling sleeve l5 journalled in the bearing l6 mounted in the adapter plate 2. The motorshaft of the drive motor is connected in the outer end. of the sleeve IS. The helical spline l3 has an enlarged portion I! which forms a shoulder for the abutment of the end of thegearIL v 1 The arms of a fork or yoke I8 bear against the other end of the gear II and normallyhold'it' in the position abuttingagainst the shoulder onthe helical spline l3. 1 a

The yoke I8 is mounted upon a rock shaft l9 which extends into the control switch compartment of the housing I., An arm 20 is mounted on the end'of the shaft. l9 and carries-the camll.

The cam II is adjustable to various positions of eccentricity with respect to the arm by means of the clamping stud 22. The cam 2| engages with the end of the plunger 23 which passes through the limit switch 24 and carries a flange 23 against which the compression spring 26 abuts. The other end of the compression spring 28 is mounted within an annular boss 21 in the housing I, and bears against the threadedadjusting screw 23.

The worm shaft 3, extends to the exterior of the housing I and carries on its outer end a hub 33 to which the hand wheel 3i is keyed, as indicated at 32. A flange 33 on the inner end of the hub 30 abuts against an inwardly directed flange 33 on the. cup shaped member 35 which is attached to the housing l-. The hub 30 has a pair of slots 33 for' the reception of the cross pin 31 carried by the outer end of the shaft 3. A compression spring 38 is mounted between the hub 33 and the housing I. The hand wheel 3i can thus be connected to the worm shaft 3 by merely pushing it axially inward against the pressure of the spring 33, so that the pin 31 is engaged in the slots 33. The hand wheel SI of course is provided for emergency, manual opera-' tion of the valve control unit.

A control switch drive shaft 40 extends from the inner end of the drive shaft 8 into the control switch compartment, and carries a pinion ll adapted to be connected in customary manner to the limit switch 42. shown in Fig. 3, a cover plate 33 is provided forthe control switch compartment of the housing i.

The operation of the above described device is as follows: v

Gear ii is normally connected with the helical spline i3 on the drive shaft l2, as shown in Fig. 1. Assuming that the valve is in open position and that it is to be moved to closed position by rotation of the drive shaft i2, in a direction indicated by the arrow in Fig. 1, or in a counterclockwise direction with respect to Fig. 4, the gear II will have a tendency to back off'the splines i3, but this tendency is resisted by the arms of the yoke it. The hand of the helix on the gear ii is the same as the hand of the helix of the splines i3, so that the helical teeth on the gears l3 and II are so disposed as to assist the tendency of the gear Ii to move in a right hand direction along the shaft l2 and to back off from the splines I3. As the valve approaches closed or seated position, its increased resistance to movement is of course transmitted through the shaft 3, the worm gear I, the worm 4, the shaft 3, the gear II to the gear ii with theresultant increase in the force with which the gear I I tends to move against the arms of the yoke l3 and incidentally against the pressure of the spring 23. As soon as this resistance is built up to a predetermined value, which is of course the force necessary to produce complete seating of the valve, the measure of the spring 23 will be overcome and therefore the gear ii will move to a position out of engagement with the splines II. The yoke II, the arm 23 and the cam 2i will of course then assume a position as dicated by the dotted lines in-Figs. l and 2. ment of the parts will move the plunger 23 to such a position as to open the contacts in the switch 24 and thereby deenergize the drive motor. The kinetic energy, or the inertia of the armature and shaft of the drive motor will then be freely dissipated by rotation of the shaft i2, since the gear Ii has been disconnected.

uch move-- it will be seen that the splines l3 are of limited length, that is, not as long as the teeth of the gear ll, so that the latter can move to disconnected position with respect to the splines l3 without losing mesh or becoming disengaged with the teeth of the gear in.

When the drive shaft i2 is rotated in an opposite direction, or in a counter-clockwise direction. with respect to Fig. 4, for the purpose of again opening the valve, the splines i3 will quickly reengage with the gear Hand the latter will return to its normal position as shown in Fig. 1. The valve opening operation or stroke of the control unit is of course controlled through the switch 32, so that the drive motor is stopped as the valve approaches fully opened position.

It will thus be seen that my above described invention not only provides means for insuring the seating of the valve under a sufficient pressure, but also disconnects the drive motor after such seating has been obtained, to permit the free rotation of the motor and the dissipation of its kinetic energy so that such energy need not be absorbed through impact resilience of the valve parts and of the gear train.

Other modes of applying the principles of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a valve control unit, the combination of power driving means, a rotatable shaft adapted to move the valve to open and closed positions, a reduction gear train connected to said shaft, an axially slidable, helically splined coupling connecting said driving means to said gear train, the length of the spline on said coupling being shorter than the axial movement thereof whereby said spline is movable to disengaged position accordingly to disconnect said driving means.

, 2. In a valve control unit, the combination of power driving means, a rotatable shaft adapted to move the valve to open and closed positions, a reduction gear train connected to said shaft, an axially slidable, helically splined coupling connecting said driving means to said gear train, the length of the spline on said coupling being shorter thanthe axial-movement thereof whereby said spline is movable to disengaged position accordingly to disconnect said driving means, and

yieldable means for resisting the axial movement of said coupling.

3. In a valve control unit, the combination of power driving means, a rotatable shaft adapted to move the valve to open and closed positions, a reduction gear train connected to said shaft, an axially slidable, helically splined coupling connecting said driving means to said gear train, the length of the spline on said coupling being shorter than the axial movement thereof whereby said spline is movableto disengaged position accordingly to disconnect said driving means, yieldable means for resisting the axial movement of said coupling, and control means actuated by axial movement of said coupling for deenergizing, said driving means when the latter is disconnected.

4. In a valve control unit, the combination of power driving means, a rotatable shaft adapted to move the valve to open and closed positions, a reduction gear train connected to said shaft, an axially slidable, helically splined coupling connecting said driving means to said gear train, and a helical gear carried by said coupling and engaging at all times with a helical gear in said gear train, the hand of the helix in said firstnamed helical gear being of the same hand as the helix of the spline of said coupling.

5. In a valve control unit, the combination of power driving means, a rotatable shaft adapted to move the valve to open and closed positions,

10 a reduction gear train connected to said shaft,

an axially slidable, helically splined coupling connecting said driving means to said gear train, a helical gear carried by said coupling and engaging at all times with a helical gear in said gear train, the hand of the helix in said first-named helical gear being of the same hand as the helix of the spline of said coupling, and adjustable spring pressure means for resisting the axial movement of said coupling.

GEORGE H. ACKER.